Sim card purchase

I normally buy my vodacom simcards at Ackermans ,today I was turned away at sancardia Ackermans. They told me I can't buy 30 sim cards even though I had all Rica documents, they said I am limited to 2 sim cards, I am shocked because the other Ackermans where I normally buy sim cards never complains about the quantity I buy.so what should I do now, should I go and buy 2 sim cards daily until I get the quantity I need . I am involving vodacom I need to understand why they could give a limit of 2 sim cards, are they not in the business of getting more subscribers?